PS/IS 686 | Brooklyn, NY

Place Value and Decimals

Place Value and Decimals

In Grade 5, we are beginning a new math unit, Place Value and Decimals.  In this unit, students will connect their understanding of whole number operations to operations with decimals.  Decimal place value is an extension of whole number place value. Our base-ten numeration system extends infinitely to very large and very small numbers (e.g., millions & millionths).

During this unit, students are expected to be pattern seekers. Looking at patterns helps students uncover and deeply understand the multiplicative relationship between places in our number system.

I am pushing students to move beyond the “zero trick” and truly articulate relationships between numbers using place value language. Instead of students saying, 5×8=40, so 5x 80 is 400, because I “added a zero”, I am expecting that students articulate what is happening to the factors multiplicatively. 

For example, 5 x 80

                        = 5 x 8 x 10

                        = (5 x 8) x 10

                         = 5 x (8 x 10), and the property at work here is the associative property.

We will be looking at the patterns that occur when using exponents to represent Powers of 10. We will also use scientific notation and expanded form.

One big mathematical  idea in this unit is for students to:

  • Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left

We will be using a place value chart as a model to explore this idea.


Screen Shot 2019-11-10 at 10.10.59 AM

Students will be  working on using precise language to articulate patterns, and then generalize these patterns in order to utilize the  four operations using decimals. There are some videos on Khan academy that could help your child understand this idea.

Khan Academy Decimals Videos


Please note that Math Homework is given consistently on Tuesdays and Thursdays. Please make sure your child completes his/her homework  and hands it in on time. Late homework is not accepted, and results in a zero for that homework assignment. Homework is 10% of your child’s overall math grade. Your child should be recording all homework assignments, important calendar dates, and due dates in his/her daily planner.

Urban Park Rangers Visit

501 and 502 both took part in a classroom visit facilitated by the Brooklyn Urban Park Rangers. This visit is in preparation for our trip next week to the Salt Marsh. Park rangers, Patrick and Anthony, spoke about the climate change. Our young environmentalists were excited to learn more about how they can do their part, both at home and in our school community. Here is 502!

I am looking forward to meeting with you at Parent Teacher Conferences!

Upcoming Dates

November 13- Trip to Salt Marsh with Urban Park Rangers

November 14- Parent Teacher Conferences/Half Day for Students

November 28-29- No School (Thanksgiving Holiday)

December 13- Trip to MoMath (Museum of Mathematics)